Preheat the Oven: Set to 400°F (200°C) and line a baking sheet with parchment paper.
Mix Dry Ingredients: In a large bowl, whisk together the flour, baking powder, sugar, and salt.
Cut in Butter: Add the cold cubed butter and use a pastry cutter or your fingers to mix until the dough looks like coarse crumbs.
Add Wet Ingredients: Stir in the sourdough starter, heavy cream (or buttermilk), and vanilla extract (if using). Mix until just combined—don't overwork the dough.
Shape the Dough: Turn the dough onto a lightly floured surface, gently knead 2-3 times, and pat into a 1-inch thick circle.
Cut & Arrange: Slice into 8 wedges or use a round cutter. Place on the prepared baking sheet.
Bake: Bake for 15-18 minutes until golden brown.
Cool & Serve: Let cool slightly, then enjoy with butter, jam, or clotted cream!